Properties of oils

This section will firstly consider the properties of oils in the reservoir (compressibility, viscosity and density), and secondly the relationship of subsurface to surface volume of oil during the production process (formation volume factor and gas oil ratio). 

Pressure depletion in the reservoir can normally be assumed to be isothermal, such that the isothermal compressibility is defined as the fractional change in volume per unit change in pressure, or 

The value of the compresjiibility of oil is a function of the amount of dissolved gas, but is in the order of 10 x 10 psi By comparison, typical water and gas compressibilities are 4x10 psi and 500 x 10 psi respectively. Above the bubble point in an oil reservoir the compressibility of the oil is a major determinant of how the pressure declines for a given change in volume (brought about by a withdrawal of reservoir fluid during production). 

Reservoirs containing low compressibility oil, having small amounts of dissolved gas, will suffer from large pressure drops after only limited production. If the expansion of oil is the only method of supporting the reservoir pressure then abandonment conditions (when the reservoir pressure is no longer sufficient to produce economic quantities of oil to the surface) will be reached after production of probably less than 5% of the oil initially in place. Oil compressibility can be read from correlations. 

Oil viscosity is an important parameter required in predicting the fluid flow, both in the reservoir and in surface facilities, since the viscosity is a determinant of the velocity with which the fluid will flow under a given pressure drop. Oil viscosity is significantly greater than that of gas (typically 0.2 to 50 cP compared to 0.01 to 0.05 cP under reservoir conditions). 

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The fluid properties of formation water may be looked up on correlation charts, as may most of the properties of oil and gas so far discussed. Many of these correlations are also available as computer programmes. It is always worth checking the range of applicability of the correlations, which are often based on empirical measurements and are grouped into fluid types (e.g. California light gases). 

Table 8. Properties of Oils Produced from Shales...

Plastic Viscosity and Yield Point. Plastic viscosity and yield point measurements are obtained from a direct indicating viscometer. Due to the temperature effect on the flow properties of oil-base mud, the testing procedure is modified. The mud sample in the container is placed into a cup heater [23]. The heated viscometer cup provides flow property data under atmospheric pressure and bottomhole temperature. 

Portable Equipment. Chemical shoreline cleaning agents enhance removal of stranded oil from shoreline surfaces, but site-specific variables, physical and chemical properties of oil, and variations in substrate types influence the performance of shoreline cleaning agents. It is difficult to predict the performance for site-specific variables. Therefore on-site testing of shoreline cleaning agents with oil and local substrates is needed. 

J. Lakatos-Szabd and I. Lakatos. Effect of sodium hydroxide on interfacial rheological properties of oil-water systems. In Colloids Surfaces, Sect A, volume 149, pages 507-513. 9th Surface Colloid Sci Int Conf (Sofia, Bulgaria, 7/6-7/12), 1997. 

J. Lakatos-Szabo, I. Lakatos, and B. Kosztin. Role of interfacial rheological properties of oil/water systems in mechanism and design of EOR/IOR technologies. In Proceedings Volume, number 057. 9th EAGE Impr Oil Recovery Europe Symp (The Hague, Netherlands, 10/20-10/22) Proc, 1997. 

Gray, G.R., Darley, H.C.H., Rogers, W.F. "Compositions and Properties of Oil Well Drilling Fluids" 4th Ed, Gulf Publishing Houston, TX 1980. 

Summarizing the growth of the utilization of petroleum oils in herbicides, an evaluation is made of the present-day chemical weed-control methods in which oils are employed—as toxicants, as solvents, as filming agents, and as carriers. The unique properties of oil in the pest control of the future are also indicated. 

Semenova, M.G., Antipova, A.S., Belyakova, L.E., Dickinson, E., Brown, R., Pelan, E., Norton, I. (1999). Effect of pectinate on properties of oil-in-water emulsions stabilized by asi-casein and P-casein. In Dickinson, E., Rodriguez Patino, J.M. (Eds). FoodEmul-sions and Foams Interfaces, Interactions and Stability, Cambridge, UK Royal Society of Chemistry, pp. 163-175. 

The process requires that water droplets have adequate time to contact each other It also assumes that buoyant Forces acting on coalesced droplets allow them to settle to the bottom of the treating vessel. Consequendy, design considerations take into account temperature, time, viscous properties of oil that inhibit setding and the vessel s physical dimensions, which determine the velocity at which setding must occur... 

Falex test—a method for determining the extreme-pressure (EP) or anti-wear properties of oils and greases. Vee blocks (with a large "V"-shaped notch) are placed on opposite sides of a rotating steel shaft, and the apparatus is immersed in a bath of the test lubricant. Load is automatically in-... 

Lukaszewicz et al. (2004) reported the oxidative properties of oil extracted from various flax cultivars. Linola cultivar (high LA), with the lowest content of linolenic acid, exhibited the highest conjugated diene values when heated... 

Daling, P.S. Brandvik, J. Characterization and Prediction of the Weathering Properties of Oils at Sea, A Manual for the Oils Investigated in the DIWO Project, IKU SINTEF Group Trondheim, Norway, 1991. 

Inter-esterification has many industrial applications such as the production of structured lipids and the manipulation of the physical properties of oils. This method is therefore intended to check the overall genuine authenticity of any commercial olive oil. 

Hoffmann, G. (1970) Keeping properties of oils are they analytically predictable Chem. Ind., London, pp. 729-732. 

Table IV. Properties of Oil Entering Catalytic Hydrocracking Unit...

Chesworth, S.M., Dickinson, E., Searle, A.,Stainsby, G. 1985. Properties of oil-in-water emulsions containing gelatin and caseinate. Lebensm.-Wissen. Technol. 18, 230-232. 

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